The parameters which are suitable for being monitored in the scope of the present invention, and which are calculated by an anemometric unit, are in particular the total pressure Pt, the static pressure Ps and the total temperature TAT, which are important parameters for piloting the aircraft. In order to be valid, these parameters Ps, Pt, TAT must have at least a predetermined level of reliability.
It is known that most modern airplanes include at least one anemometric unit for determining the values of information such as the altitude of the aircraft or its velocity, which are used when piloting. For reasons of operational safety, airplanes generally include two or three anemometric units. In order to calculate the aforementioned parameters, each anemometric unit acquires data coming from one or more pressure sensors. Usually, each of said pressure sensors is located inside the fuselage of the airplane and is connected by a tube to a probe arranged passing through the surface of said fuselage. This tube is generally connected to the associated pressure sensor by means of a pneumatic connector, allowing it to be disconnected and reconnected easily.
It is known that human errors, in particular during maintenance operations of the airplane, may cause malfunction of one or more of the pressure sensors of such an anemometric unit.
For example, the personnel tasked with performing an operation of washing the airplane often stick a piece of adhesive tape on each of the probes of the anemometric unit, in order to prevent water from entering the tube during said wash. If they forget to remove one of said pieces of adhesive tape after the wash, the corresponding pressure sensor will be inoperative during the next flight of the airplane, since it will not be able to measure the pressure of the air outside the fuselage. It will in fact measure the pressure of the air in the tube, which is closed by the piece of adhesive tape at its end next to the probe.
Another example of malfunction relates to the case when maintenance personnel disconnect the tube and the pressure sensor at an appropriate connector, for example in order to clean the inside of this tube. If they forget to reconnect the tube to the pressure sensor after having carried out the maintenance operation, said pressure sensor will also be inoperative since it will measure the pressure of the air inside the fuselage, instead of measuring the pressure of the air outside the fuselage.
Another case of malfunction of a pressure sensor which may arise during the flight of the aircraft, relates to the case of said probes (for example the “Pitot” tube) icing up, which can prevent correct operation of said pressure sensor. No known solution makes it possible to detect the validity defect of an aforementioned parameter of the aircraft due to this last malfunction.